Post by Graveyardbride on Mar 29, 2019 4:27:33 GMT -5
Deadly Influenza Could Be Spread by Dogs
Results of a 10-year study suggest two strains of influenza that could mix and form a dangerous new strain of the sometimes deadly disease is spread by dogs. Dr. Daesub Song, Associate Professor at Korea University, has called for closer monitoring of dogs and other so-called “companion animals” as a source of novel human influenza strains. “Until now, dogs were considered neglected hosts in the field of flu research,” he said. “However, after the first report of interspecies transmission, surveillance of flu viruses from companion animals should be further strengthened.”
In the 2000s, several cases of viruses crossing the host barrier, (i.e., jumping species) were recorded. Most notably, H3N2 bird flu crossed to dogs and developed into Canine Influenza virus (CIV). Dr. Song’s research suggests this H3N2 CIV could combine with H1N1/2009 and form a new influenza virus called CIVmv. The emergence of such new influenzas is concerning. Those infected will not have come into contact with such a virus before and they would have no immunity. If the virus were carried by companion animals and crossed to humans, it would spread rapidly.
H1N1/2009 is known for causing the 2009-2010 global “swine flu” pandemic. When this strain of influenza combines with CIV in dogs, some of the viruses recombine to form CIVmv. Although CIVmv is very similar to CIV, researchers have calculated there is a much higher risk of the disease spreading to humans because of its high infection rates in ferrets. Viruses bind to host cells and cause infection via sialic acid (SA) receptors, which differ among species. Ferrets have very similar SA receptors to humans. Because of this, ferrets are considered the most reliable experimental model for predicting and evaluating the risk of novel human influenza viruses.
During studies of the new CIVmv strain, Song noted that infected dogs and ferrets displayed typical symptoms of respiratory disease, including congestion, breathing difficulties, coughing, runny eyes, sneezing, lethargy and loss of appetite. In addition to these symptoms, he noted the new strain spread between ferrets faster than other influenza viruses and replicated quickly. Scientists are attempting to develop a vaccine for the virus. However, because of the high level of mutations, vaccines are very difficult to develop.
Despite its name, Canine Influenza Virus doesn’t infect only dogs. During the 10-year study, researchers found cats are also susceptible to the virus. Song investigated an outbreak of CIV in an animal shelter, during which 100 percent of cats were infected and 40 percent died. The susceptibility of cats to CIV is worrying because it demonstrates CIV can spread to and among different species. Researchers have raised concerns there is a potential for the virus to become endemic in companion animals. As both dogs and cats are in frequent contact with humans, much more frequently than pigs or chickens, the potential risk for a new strain to develop and infect humans is even higher.
Since it was first identified in South Korea, CIV has spread to China, Thailand and the United States. A case of CIVmv infection was identified in a dog in 2012 following an epidemic of H1N1. Song used this strain in ferrets to determine if it had the potential to spread from canines to humans. From there, a novel human influenza strain could emerge. “Pre-existing CIV may recombine or reassort with human influenza viruses and give rise to novel viruses that could in turn lead to unique pandemics,” he explained.
Source: Microbiology Society, Phys.Org, March 28, 2019.
